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v G. H. ZSOHEUH.

BELT TIGHTENER. No. 269,369. Patented Dec. 19, 1882.,

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(No Model.) 2 sheets sheet 2.

G. H.1ZSOHEGH.

BELT TIGHTENER;

No. 269,369. Patented D'ec.19, 1882.

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UNITED STATES PATENT OFFICE.

GUSTAVUS H. ZSOHECH, OF INDIANAPOLIS, INDIANA. v

BELT-TlGHTENER.

SPECIFICATION formingpart of Letters Patent No. 269,369, dated December19, 1882.

Application filed December 19, 1881. (No model.)

To all whom it may concern Beit known that l, GUSTAVUS H. Zscnncn, ofIndianapolis, Marion county, in the State of Indiana, have inventedcertain new and useful Improvements Relating to Tighteners for Belts, ofwhich the following is a specification.

I will describe the invention as applied to the driving-belt runningupon a pulley ofsmall diameter, driving the upper pair of circular saws.

One object of the invention is to facilitate the guidance of the belt.Another object is to tighten the belt in proportion to the resistancewhich is experienced by the saw, so that thereshallbesufficienttightness at theperiods when great resistance isexperienced without the friction upon the bearings which would obtainifthesame tension were maintained uniformly.

The difficulty of producing circular saws of sufficient diameter to cutthrough the largest logs has induced the arrangement of a pair of suchsaws, one with the shaft below and the other with the shaft above thelumber to be cut. Snell saws are nicely adjusted to out in the sameplane, with cuts meeting each other. In sawing by such means logsdiffering greatly in size the upper saw will be subjected to greatvariations of resistance. In the large end of the largest log it willhave nearly or quite as much work to do as the lower saw; but at manyperiods it will have little or nothing to do. My tightener may beapplied to the belt for the upper saw. v

' The accompanying drawings form a part of this specification, andrepresent what 1 considerthe best means of carrying out the invention.

Figure 1 is a side elevation, partly in section. Fig. 2 is an end View,looking in the direction of the arrow in Fig. 1.

Similar letters of referenceindicate like parts in all the figures.

A is the fixed frame-work.

B is an ordinary stout pulley, ofample width but of small diameter,mounted upon the arbor I), supported-in suitable fixed bearings. (Notshown.)

0 is the ordinary driving-belt therefor, running from the pulley M onthe lower saw-arbor, m.

- The tightenerpulley D is mounted in a forked frame, E, which ispivoted at the pointe on a bifurcated lower frame, G. The surface ofeach part adjacent to the pivot e is extended to make a broad circularbearing of the parts D and G against each other, and fastening-bolts Fare inserted through curved slots f. By slackening these bolts F thejoint 0 is made loose, so that the part E may be turned to any requiredextent relatively to the part G. The tightening of the bolts F stitfensthe joint 6 and makes the parts E and G serve as asiuglerigidframe,vibratingonthe axisg. The

frame-piece E is formed wi h a stout socket E, in which is received therounded end of the upright arm H of the bell-crank lever H H This leverturns on the same center 9. Its horizontal arm H is received in a longupright slot in a casing, I, which incloses a long spiral spring, J,having a tendency to expand itself, which is communicated through thesliding piece K to the arm of the lever H H L is a pin extending acrossthe slot in the upright casing I. It may be adjusted in position byinserting it in any one of the series of holes 2' represented.

In the use of my tightener the spring J exerts a nearly constant force,tending to lift the arm H and consequently to press the tightener-pnlleyD against the belt 0. The action of the pulley is against the slackportion ot'the belt, by which I mean that portion on which there is aless tensile strain than the other parts, depending on the amount ofresistance encountered by the saw. The arrangement also brings thetightener-pnlley D into close proximity with the driven pulley B. Duringthe long periods while the upper saw is running light the tension on allparts of its belt 0 is practically uniform, and the tightenerpulley D isforced back by the tension of the belt 0, and the spring J iscompressed; but when a large log is introduced and the saw on arbor bencounters great resistance the tension on the partsof the beltG becomesvery unequal. The tight side of the belt, which is indicated by thearrow pointing downward, is subjected to great strain, and the looseside, which is indicated by the arrow pointing upward, is greatlyrelieved from strain. Under these conditions the spring J expandsitself, lifting the arm H H, and, turningthe framingE G in its center,g,presses the tightener-pulley D forward against the belt. This maintainsa proper tension on the slack side of the belt and performs the ordinaryfunctions of a tightener. It also, by virtue of the close proximity ofthe tightenerpulley D to the saw-pulley B, causes the belt 0 to hugaround a larger portion of the periphery of the latter, thus increasingits etficiency. In all positions of the parts the turning of the framingE slightly on its center 6 enables the tightener-pulley D to deflect thebelt 0 to one side or the other. It is thus an efficient guiding means.If the belt indicates adisposition to runtoward either end of thesaw-pulley B,- I slackeuthe bolts F and turn the forked frame E slightlyon the center 0 in the proper direction to incline the guiding-pulleyDand con ect the tendency. When the right position is obtained theboltsFare tightened and the whole is ready to work smoothly and correctly foran indefinite period.

The pin L may be shifted up and down in the several holes 2', asrequired. It fixes a definite limitto the forward travel ofthetightenerpulley.

I attach much importance to the arrangement of the parts. The pulley i)must not be pressed against the belt C at a point midway or nearly sobetween the pulleys B and M. It must be adjusted so as to make itsforward and backward travel as near as practicable to one of thepulleys. This arrangement insures that the belt shall be forced intomun-ll more extended contact with the pulley when the strain isgreatest, and also allows a given amount of forward and backward motionto produce a greater etfect upon the tightening and relaxing ot'thebelt. When the resistance of the saw is lessened the tension of the beltis more efficient in urging back the tightenerbelt by reason of thisarrangement of the parts,whercby the tightener-pulleyD traverses closeto the sawpulley B.

Modifications may be made in the several details without departing fromthe principle or sacrificing all the advantages of the invention. Thedistance of the pulley D from the pulley B may be varied within narrowlimits, so long as sufiicient spaceis allowed for the thickness of thebelt between the peripheries at the closest point. I propose to changethe position of the center y when the arbor b of the upper saw is raisedby the introduction of a new or large saw, and is successively loweredas the diameter of the saw is reduced by repeated sharpenings.

I claim as my invention- 1. The belt-tightener described, having theswivelingjoint-e between the parts E and G, in combination withconfining means 1, as herein described.

2. The tightener-pulley D, supported in a framing turning on the centerg, which. is operated by the lever H, in combination with the slottedstandard or casing I, spring J, and adjustable pin or stop L, arrangedto operate relatively to each other and to a driving-belt,

'0, as herein specified.

3. In combination with a spring, J,lever H H and belt 0, running on thepulleys M and B, the tightenerpulley D, and itsguiding frame E G,arranged to traverse the tightening-pulley in a path close to the pulleyD, as and for the purposes herein specified.

In testimony whereof I have hereunto set my hand at Indianapolis,Indiana, this 6th day of December, 1881, in the presence of twosubscribing witnesses.

GUSTAVUS H. ZSUHEOH.

\Vitnesses:

CONRAD Riissu, CHARLES OFF.

